*GROUP SPELL* (min of three casters)

Then this complicated group spell is finished, the sky over the area that is targeted, begins to light up as meteors of various sizes begin to descend at high speed to the area. Meteors begin to hit the area after 3 rounds from when the spell is completed and the spell is being concentration on.  For the next 7 rounds, each wizard roll d4, that is the number of meteors that strike 60 foot targeted area for 4d6 fire damage, dex save for half 

If all the casters stop concentrating, the spell continues but the meteors strike randomly all over the place, many wizards have died by there own spell.